Draft-regulator



(No Modl. I 2 shets -sheet 1.

' I J. vDEMPSEY. V

I v DRAFT-REGULATOR. N0.-2'92,Z87. w Patented Jan. 22, 1 884.,

' NITED STATES ATENT OFFICE.

"JAMESDEMPSEY, on LEwisroN, MAINE.

DRAFT- REGULATOR.

'SPECIFICATION'fQrming partof Letters Patent No. 292,287, dated January 22, 1884.

Application filed June 28, 1883.

To all whom it may concern.-

Be it known that I, JAMES DEMPSEY, of Lewiston, county of Androscoggin and State of Maine, have invented a new and useful Improvement in Draft-Regulators for Steam- Boiler Furnaces; and'I hereby declare the following to be a full, clear, and exact description ofthe same, reference being had to the accompanying drawings, forming part of this specification.

This invention has reference to an improve ment in draft-regulators for steam-generators; and it consists in the peculiar andnovel arrangement by which the fire-doors of asteamboiler are connected with the damper, so that on the opening of any one of the doors the damper will be closed, as will be more fully set forth hereinafter.

In steam-generators the furnace is connected through the fiues or tubes with the chimney. The velocity of the draft under the boiler and through the flues or tubes is limited by the passage of the air through the fuel. When, 110w, the fire-doors are opened, the cold air enters the doors, sweeps at a great velocity over the heating-surface of the boiler, suddenly cooling the same. It strikes the tube-sheet, and by the sudden contraction of the thin tubes, owing to this change in temperature, causes the same to'leak. It reduces the temperature of the fines and. chimney, and causes in a very short time an almost inestimable loss of calorie and consequently fuel. By connecting the fire-doors with the damper in the flue leading to the chimney, this rush of cold air through the fines of the. boiler, the great loss in heat and waste in fuel, as also the injury to the generator, are prevented.

Figure l is aview of a vertical steam-boiler, showing the connection between the fire-doors and the damper in the exit-flue. Fig. 2 is a sectional view of a horizontal tubular steamgenerator, showing the connection of the damper with the fire-door.

In the drawings, A is the steam-boiler.

B is the flue leading from the boiler to the chimney.

O. O are the fire-doors.

D D the ash-pit doors.

E is the. damper. This damper may be constructed to close the whole area of the flue; but I prefer to make the same so that suffi- (No model.)

cient opening is left either on the sides of the damper or'in the damper itself, to carry off the gases generated in supplying fresh fuel to the fire, allowing the products of combustion to pass to the chimney slowly, but restraining the rush of air through the fines.

F F are two chains, each connected with a fire-door either by securing the same to the lever f, secured to the door,as is shown in Fig. 1, or to the door itself. ,The chains F F connect with a common chain,G,the end of which is secured to the counterweighted arm H;

This arm may be connected with the shaft of the damper, as shown in Fig. 1, or it may be connected with the lever I, as shown in Fig. 2, the opposite end of the lever being connectedin any suitable manner with the damper 1G. .The chain G is passed over suitable sheaves to any place most convenient to operate the damper.

On examining Fig. l,it will be seen that the opening of either door will exert a strain on the chain G and close the damper, so that the fire-doors cannot be opened without closing the damper, and thus preventing all the troubles incident to the inrush of cold air.

It is evident that in the various forms of steam generators the connection between the fire-doors and damper must be adapted to the respective location of the same.

The damper E forms an auxiliary damper, and is used independent of the ordinary damper by which the draft-is regulated, so that the usual steam-damper may be used in connection with the chimney, and is not affected by the use of the auxiliary damper.

To open the damper when the doors are closed in the device shown in Fig. 1, the lever H is provided at one end with a weight. In the device shown in Fig. 2, the same lever II is also weighted on one end, and to facilitate the closing of the damper in that figure the damper is set at an angle. By the use of this device considerable fuel is saved and the boilers are protected against injury.

I am aware that it is not new to connect the door of a boiler-furnace with a damper in the chimney by a rigid bar. Such is shown in English Patent No. 685 of 1852.

Having thus described my invention, I claim as new and desire to secure by Letters Patent* The combination, with the fire-door of a IOO boiler-furnace, of a chain attached to the fire- In witness whereof I have hereunto set my door, weighted lever H, mounted above the hand. furnace, lever I, connected to lever H, as del P A P scribed, a chain leading to the damper, and V IAILS DL H 5 the inclined damper, the chains being con- I Witnesses:

nected to the levers in the manner and for the J. A. MILLER, J12,

purpose set forth. M. F. ZL'IGIL 

